Evaluation of a noninstrumented disposable method for quantifying serum theophylline concentrations.
OBJECTIVE
To compare the performance of a new point-of-care theophylline assay (AccuMeter) with that of a standard laboratory assay (TDx), and another point-of-care method (AccuLevel).


METHODS
Prospective evaluation of consecutive patients receiving theophylline.


METHODS
University-based, ambulatory, allergy-pulmonary clinic.


METHODS
Forty subjects receiving maintenance theophylline therapy for asthma.


METHODS
Theophylline concentrations obtained from AccuMeter, TDx, and AccuLevel were compared.


RESULTS
The error, or difference, between TDx and AccuMeter results in 40 subjects on maintenance theophylline described accuracy. Mean error, an estimate of bias, was 1.1 (95% CI 0.72-1.5), 0.67 (0.34-1.0), and 0.98 (0.79-1.2) microg/ml for AccuMeter capillary, serum, and heparinized blood samples. Square root of the mean squared error, an estimate of precision, was 1.6 (1.2-2.0), 1.22 (0.90-1.5), and 1.14 (0.96-1.3) microg/ml for AccuMeter capillary, serum, and heparinized samples. Difference between AccuMeter and AccuLevel ME, an estimate of relative bias, was 0.59 (0.04-1.1) microg/ml. The difference in mean squared errors, an estimate of relative precision, was 0.86 (-0.54-2.3) microg/ml.


CONCLUSIONS
AccuMeter demonstrated good precision and minimal bias compared with TDx and AccuLevel . Method of sample collection had no effect on its accuracy.
Asmus
M J
MJ
Division of Clinical and Administrative Pharmacy, College of Pharmacy, University of Iowa, Iowa City 52242-1112, USA.
Milavetz
G
G
Teresi
M E
ME
Weinberger
M M
MM
D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D018927:Anti-Asthmatic Agents / Q000097:blood* / Q000627:therapeutic use; D001249:Asthma / Q000097:blood / Q000188:drug therapy; D002648:Child; D016903:Drug Monitoring / Q000379:methods*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D015203:Reproducibility of Results; D013806:Theophylline / Q000097:blood* / Q000627:therapeutic use
D018927:Anti-Asthmatic Agents; D013806:Theophylline